Recovery of Chitin from Antarctic Krill (Euphausia superba) Shell Waste by Microbial Deproteinization and Demineralization

A two-stage fermentation process of deproteinization and demineralization was used to purify chitin from Antarctic krill shell waste. Two bacterial cultures were isolated and tested for the degradation of krill shell waste. According to the morphological examination, physiological tests, and applied molecular techniques conducted, isolates were identified as Bacillus subtilis and Lactobacillus plantarum. At a temperature of 37°C, both strains were cultivated separately in flasks containing krill shell waste. At determined periods of time, deproteinization and demineralization of residuals were measured. For deproteinization tests, the liquid phase fermentation of krill shell waste showed protein removal of 88.9% after 60 h. For demineralization tests, the liquid phase fermentation of krill shell waste showed calcium carbonate removal of 84.6% after 72 h. Fourier transform infrared spectroscopy (FTIR) analysis of chitin prepared by the process was carried out and compared with spectra of samples treated by strong acids and bases.